Retinitis pigmentosa (RP) consists of a large group of hereditary disorders resulting from a progressive loss of the rods and cones (photoreceptors) in the retina. These are the cells that respond to light and send signals to the brain enabling us to see. More than 100 mutant genes have been identified as responsible for these individually rare disorders and there is considerable variation in onset and progression of symptoms. The disease usually is present as an isolated eye disease but syndromal forms also occur in which there is a similar disease of the retina in association with other problems elsewhere in the body.
This is an early-onset and progressive disease of cells in the retina. Most children are aware of difficulties with nighttime vision by the end of the first decade of life. Some loss of vision and color perception is usually noticed by this time as well. Side vision is restricted and all of these symptoms progress leading to severe loss of vision by the 4thdecade. Examination of the retina reveals thinning of the retina and changes in pigmentation. The optic nerve shows some damage and the blood vessels of the retina are often narrowed.
General health is usually good.
This is an autosomal recessive disorder caused by mutations in both copies of a specific gene. It is inherited when both parents (clinically normal) carry a copy of the mutation. Children of such parents have a 25% chance of inheriting retinitis pigmentosa 38.
The diagnosis is usually made by an ophthalmologist based on the patient’s history, the appearance of the eye, and the results of a test known as an ERG (electroretinogram). Patients are usually otherwise healthy and can expect to live a normal lifespan.
There is no treatment for this genetic condition but children especially can benefit from low vision aids and special educational facilities.